I've used Word and Excel several times with the new builds, neither are ready of prime time IMO. I have not used PowerPoint in the new suite yet.
I have had no issues with Word yet. It's missing direct tie-ins (references) to macros and VB. For simple work, Word works well. I've composed several simple (read: word processing) documents and have had a few crashes. For complex work, I will not rely on it yet.
For Excel, it chokes on larger files. The Mac Office app versions are still, sadly like the 2011 version, 32-bit - the same files in Excel 2013 (Win, 64-bit) work fine. The same files in Excel 2013 (Win, 32-bit) also choke - however, at least on the Windows platform I have choices (of application installs). And, of course, the 32-bit Mac application is, by that architectural restriction not "allowed" access to very powerful Add-Ins. 😡😡😡
As for Outlook, there's no parity at all. In Office 2013 there's several connection options outside the realm of the Mac Office Beta. The latter is restricted to IMAP and EWS; the Win versions of Office have several other connection options, including EAS.